1. Field of the Invention
The present invention relates to an improved method of producing artificial rock and waterfalls with a sectioned cradle and with layers of non-foaming and foaming polyurethane.
2. Description of the Related Art
The related art describes a variety of processes for making artificial landscape materials from plastic and rigid materials. The art of interest will be considered in the order of their perceived relevance to the present invention.
U.S. Pat. Nos. 4,847,026, 4,940,558 and 4,960,622 respectively issued on Jul. 11, 1989, Jul. 10, 1990, and Oct. 2, 1990, to Enos D. Jarboe et al. describe methods of molding an artificial urethane rock and the product thereof. A flexible mold is prepared from the application of numerous coats of liquid uncured latex rubber, silicone or urethane upon the rock exterior in combination with an embedded fabric. A supporting cradle for the rubber mold is produced by spraying a low density urethane foam composition over the mold. The mold and cradle are stripped from the rock and sprayed with a heated two-component structural urethane system including an isocyanate and a polyol with catalysts (organo-metal compounds, tertiary amines and alkali metal oxides), unsaturated resins, plasticizers, foaming or blowing agents, coloring agents such as colorants, dispersion dyes and pigments, an anti-oxidation additive, and an ultraviolet adsorber additive. The molded urethane rock is removed from the mold and reinforced with an inner layer of low density urethane foam. There is no concern for forming a cradle from multiple sections, removal of particles from the inner mold surface, forming a lacquer barrier coating in the mold, forming a lip in the non-foaming polyurethane coating, and painting or staining the product.
U.S. Pat. Nos. 5,443,774 and 5,543,100, respectively issued on Aug. 22, 1995 and Aug. 6, 1996, to Gordon Kluh et al. describe methods for making large-scale artificial rocks in a four-step process comprising: (1) forming a silicone rubber model of a rock; (2) coating the back side of the model with either a glass fiber reinforced plastic, hard polyvinyl chloride or polyesters to form a work mold; (3) sequentially coating the back side of the work mold with a parting compound, fiberglass matting, and a synthetic resin to make a positive model; and (4) sequentially coating the outer surface of the positive model with either a synthetic resin, pressure-setting plastic, hard polyvinyl chloride or polyesters, and multi-colored sand. These methods differ from the present invention in failing to form a cradle from multiple sections, spraying a coating of lacquer and coatings of non-foaming and foaming polyurethane.
U.S. Pat. No. 4,668,451 issued on May 26, 1987, to Bruce K. Langson describes a process for making a full life size artificial rock formation from a natural rock formation surface comprising coating the rock with a plurality of coats of latex, holding the latex mask in a fiberglass mold, applying a vacuum to the inner surface of the mask to cause all the cracks and crevices to open up, and applying cement to the outer surface of the mask to fill the open cracks and crevices. The cement coating process is clearly distinguished by the present invention.
U.S. Pat. No. 3,950,477 issued on Apr. 13, 1976, to Philip A. Di Giacomo describes a process for artificially forming rocks by forming a rubber film mold of a natural rock, placing the flexible mold on a bed of flowable polystyrene supporting pellets, and filling the mold cavity with concrete. The use of concrete is not contemplated in the present invention.
U.S. Pat. No. 4,475,847 issued on Oct. 9, 1984, to Wolfgang Cornely et al. describes a process and a cartridge product used in the process for consolidation and sealing of geological formations and artificial beds of rock, earth, and coal by injecting the blends of foaming and hardening polyisocyanate and polyol blends from a two-chamber cartridge into boreholes or injection pipes in the geological formations. Various foaming agents and catalysts are described.
U.S. Pat. No. 4,385,088 issued on May 24, 1983, to David Baskin describes a set of decorative artificial rocks from a rectangular block of styrofoam which are hand sculptured (or injection molded) in the form of rocks wherein a smaller rock nests inside the other rock. The outside surface of the rocks are coated with up to a six-inch thick wall of epoxy resin, sand and pigment to simulate natural rocks. There is little similarity between this process and that of the present invention.
U.S. Pat. No. 3,546,052 issued on Dec. 8, 1970, to Julie H. McNamara describes artificial rocks having flexible but inelastic polypropylene shells which can be filled by the purchaser at home with air, sand, gravel or soil. Other plastic materials are fluorinated polypropylene, copolymers of fluorinated ethylene and polypropylene, and vinyl plastisol. The shell can be made by blow molding or centrifugal casting. The shell can be painted and coated with rock particles. The fabrication process is clearly distinguished by the present invention.
The specific urethane forming components, the various additives, and the coating process parameters described by the above patents are hereby incorporated by reference.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus, a method of producing artificial rocks and waterfalls solving the aforementioned problems is desired.